Hierarchical control method and system for energy storage device

Abstract

The invention discloses a hierarchical control method and system for an energy storage device. The method comprises the following steps: collecting a frequency change rate, a frequency deviation and a charge state of each energy storage unit; determining whether the energy storage device participates in frequency modulation according to the frequency change rate, the allowable value, the frequency deviation and the allowable value; when participating in frequency modulation, determining the frequency modulation power of each energy storage unit participating in frequency modulation according to the frequency modulation power direction, the maximum value and the minimum value of the state of charge in each energy storage unit and the frequency fluctuation degree coefficient; the first n energy storage units in the charge state sequence of the energy storage units are taken, and if the absolute value of the sum of the frequency modulation power of the first n energy storage units is not smaller than the absolute value of the reference frequency modulation power of the energy storage device, the first n energy storage units participate in frequency modulation; if the absolute value of the sum of the frequency modulation power of all the energy storage units is smaller than the absolute value of the reference frequency modulation power of the energy storage device, all the energy storage units participate in frequency modulation. Balanced management of the energy storage units with different charge states is realized, and the service life of the energy storage device can be maintained.

Description

technical field [0001] The present invention relates to the technical field of energy storage control, and more specifically, to a hierarchical control method and system for an energy storage device. Background technique [0002] Frequency is one of the key indicators of power grid quality. The dynamic balance of power load and power generation is an important guarantee for grid frequency stability. Therefore, changes in grid frequency also directly reflect the balance of power supply and demand. When the power generation is greater than the power load, the grid frequency increases; otherwise, the power load is greater than the power generation, and the grid frequency decreases. Wind power is clean, low-carbon and relatively mature technology, and its grid-connected capacity is increasing year by year. However, the current mainstream wind turbine rotor speed is decoupled from the system frequency, so it does not have frequency response capability, which brings great challen...

AI Technical Summary

Problems solved by technology

Due to the differences in the energy storage unit itself, the temperature difference and other factors, the available capacity of the energy storage unit will be different. The energy storage unit with a small capacity will be fully charged first when charging, and empty first when discharging, thus restricting other energy storage systems in the energy storage system. The charge and discharge capacity of the unit causes the available capacity of the energy storage system to decrease; while the principle of the energy storage system participating in frequency regulation in the prior art 1 is that the state of charge reaches 100%, and according to the rated capacity of the energy storage system, the current state of charge and 100% % difference to determine the charging capacity that can participate in frequency regulation. In practical applications, the charging capacity allocated to the energy storage system in the frequency regulation control strategy cannot be fully absorbed by the energy storage system, resulting in the adjustable power allocated to the unit side. Too low to meet the actual demand for frequency regulation, resulting in secondary frequency regulation, reducing the economy of frequency regulation

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